Bearing assembly



Sept. 4, 1945.

c. c:A BELL BEARING ASSEMBLY Y Filed Dec. 30, 1943 J Charles C Bell IInventor B his Attorney n. l. Ill lv Patented Sept. 4, 1945 fummo`STATES PAT-ENT BEARING ASSEMBLY Charles C; Bell," Marblehead, Mass.,assignor to United. Shoe Machinery Corporation, Fleming; 1 ton, N. J'.,a-corporation of New Jersey g f Application December 3o,1943,seria1-No..516,305- i: y Y

4 01. n --sr 8 Claims.

i. This invention relates tomountings for rotatablemembers and moreparticularly to bearings for rotatably supportingfa member Withla.minimum of frictional'resistance whileprovidingadequate. support forthe, member under forces.v actingl normal tor its axis, of rotation.invention is not thus restricted. in its applica-.- tion; it isillustrated herein.. as. embodiedin the bearings supporting the gimbalof a gyroscope..

Gyroscopes are commonly employed in mechanisms for controlling thecourse of av movable body, such as a torpedoin its passage throughWatery to a target towardpwhich it is directed. In such mechanisms. theinner lgimbal of the gyroscope `is normally disposed horizontally inspace within the torpedo-by the outer gimbal which is mounted invertical anti-friction bearings, the inner gimbal being mounted intheouter Fimbal by horizontally disposed anti-friction bearings. Anydeviationzof the torpedo,l from its course after it has startedtoward.the target re suits in movement of the torpedo relatively .to the outergimbal, causing the actuation of suitable mechanism t operate the coursecontrol rudder in a manner to return the torpedo to its course. Betweenthe time of launching the torpedo and the time when it reaches itsdesired depth and becomes substantially stable at that depth thetorpedo. may undergo rapid and substantial changes in its ang-les ofdeclination `and. inclination. It is important. thatv these changesshould take place Withoutaffecting the horizontal position of the innergimbal of the gyroscope in space but unless the friction. in the innergimbal bearings is kept at an extremely low value the changes in thevertical movements of the tor-V pedoI may cause the inner gimbal tofollow the torpedo vto a slight extent. Such movement of theV innergimbal even though slight, will cause precession 0f the vgyroscope aboutthe Vertical axis of the outer gimbaLthe result being a change in therelative positions ofthe-torpedo and the outer'gimbal so that the ruddercontrol mechanism operates as if the torpedo had deviated from itscourse. Thus, the course control rudder may be shiftedata timev when thetorpedo isv on its true course resulting in a false correction andcausing the torpedo to follow an incorrect course. The above conditionmay be corrected by the employment of ball bearings for supporting thenner gimbal, thev ballsA of which are of such. small diameter that thefriction of the inner gim-k bal supportsv is extremely low. However, theemployment of such bearings presents another dilliculty. i Normally, theload on the bearings is sufliciently small to `permit the employment ofvery small bearings but at lthe time of launch` While the.

fil

ing the torpedo thev bearings are momentarily bearings, the balls, of'Whiclijare' of sullicient isize to absorb the maximum shook load and,gaccord' ingly, bearings of considerably largervsiae than wouldotherwise berequired have beenemployed with the attendant possibilitythatprecessionv of the 'torpedo may take place dueto the frictional dragof the bearings, thus causing a false course correction as discussedabove.

An object ofjv the present invention is to provide a bearingassembly-for a rotatable member of' such a character that the; memberbeingA sup4- ported is normally carried by very small bearings but in,which provision is made to relieve,A these bearings of. any momentaryshock load. To this end and in accordance vwith a feature of,- the in#vention the assembly comprises twosets of antifriction` bearings, a setof. small bearings "having small diameter bearinglmembers and a@ set oflarge bearings having relatively large vbearing members. The normal loadonV` the. rotatable member is taken by thesmallvbeazrings, the largerbearings normally being ipeifectiveLbut upon the application. of anabnormalradial load' on the rotatable member thek large bearings becomeeffective to Support the, rotatable rrlorrlbonr thereby limiting theload whichv may be. imposed .onthe small bearings. rIjhis isaccomplishedil'l Eaccord-` ance With'thepresent invention by mountingthe small bearings on cantileversy `wliicl'rWill bend under theapplication ci a heavy ,liadial load on the rotatable'member until therotatable mernbever.` rests upon the larger bearings, which are 11u01..-mally concentrically disposedv with respect to. the. small bearings andarev out'of contactwith, the rotatable member. l f l Y In accordancewith another feature the invent-` tion provides a mounting for a gimbalof a gyrof scope in 'which small ball bearings normallyfsup.- port vthegimbaL the bearings being carried-` by cantilevers providing a 4yielding mounting there. for, whereby any abnormal loading. on`the'gijmbal isy transferred. to larger bearings.V which are in,-4

effective during thenormal operationo the vgilroscope. `The cantileversare in the form of tubes providing passa-gevvaysl for impellng fluid todrive the rotor ofthegyroscope. i j

. In accordance with stillanother eatur'e'of the invention thesmallballlbearingls normally act as thrust bearings for the rotatablemember. The rotatable member is normally carried-by the small bearingsagainst endwisemovement relatively thereto Vin .spaced relation lto thelarge ballbearings .but provision ismade'for. permitting end-vWise'movement.. ofLtherotatable member; rela* tively to the smallbearings in. response toan excessive axial force onV the rotatablememberwhereuponyit moves` into 4engagement with Vand the force is` absorbed`byoneof the largev ball bearings.- VThe above and other features of theinvention,

' tation.

2A n l including various details of construction and novel combinationsof parts will now be described in detail withreference to theaccompanying drawing and pointed out in the claims.

In the drawing, Y Fig. 1 is a side elevation of agyroscope in which theinner gimbal is supported by bearing assemblies constructed inaccordance with the present invention; f I

Fig. 2 is a vertical section bearing assemblies for the inner gimbal;

Fig. 3 is a section on the line III-III ofV Fig. II;

throughtoneV of the f "the inner gimbal.

ing. In actual practice the spacing between the flange 36 and the largebearing 32 may be very small, of the order of .002.inoh for example, sothat a very'slight flexing of the'cantilevers will cause the largebearings to assume the load on It will be understood that in theillustrations in Figs. 2 and 4 the space between the iiange 36 and thebearing 32, and the bending of the cantilevers are exaggerated merelyFig. 4 is a View similar to Fig. 2 but showingl the relative positionsof the parts in response to.V

the application of. an abnormal loadon the inner gimbal, the shift ,-inpositions of the parts being exaggerated for clarity;

I2, an inner, horizontally disposed gimbal I4 ro- Y tatably mounted bymeans to be described, in the outer gimbal I0, and a rotor I6 mountedfor ro-V tation in the inner gimbal about a horizontal axis normal tothe axis vo f rotation of the gimbal I4. TheV rotor, I 6, is providedVon its periphery with vanes I8 to receive a blast of gas underYpressure to cause rotation of the rotor at high velocity, as

will berdescribed. t

Mounted at diametrically opposite points in the gimbal III` aresleevesin `each of which is mounted a tube 22 closed atits outer end by a plug24. The inner'end portion of the tube is reduced in diameter to space itfrom the sleeve 20 and to'form a yieldable cantilever support for asmall ballbearing 26. The outer raceV of the ball bearing 26 is receivedby an aperture 28 in the inner Vgimbal I4 Vso-that the inner gimbal isnormally supported by a pair of ball bearings the bearing members 30 ofwhich, as shown, are of such relatively small rdiameter as to reduce thefrictional resistance of the gimbal to turning to for-"purposes ofillustration.

' The small bearings 26 also act as thrust bearings for the innergimbal, but the inner gimbal is mounted for yielding movement relativelythereto inthe event of any abnormal end thrust onA the inner gimbal.These `bearings arereceived between shoulders 38 on the cantilevers 22and bars 40 secured to the inner portion of the gimbal I4 by screws 42.These bars engage the'l outer races of the small bearings 26 and areapable .of Vyielding slightly, as indicated in Fig. 6,

' in thejevent of any abnormal end thrust on. the

inner gimbal which the small bearings would be incapable of absorbing.Upon such yielding of Y the' bars 46, the gimbal engages the outer raceof one of the large bearings 32 the inner race of which engages ashoulder 43 on the cantilever 22. Thus the largev bearings absorbabnormal thrust loads on theinner gimbal as well as abnormal a verysmall amount. The cantilever supportI for 4 radial loads, therebyobviating the possibility of destruction of the small bearings by whichthe inner gimbal is normally Supported.

The tubes 22 which support the small bearings 2li vprovide for thepassage ofV compressed air or any other suitable operating iuid to bedirected to the rotor I6 to cause its rotation. These tubes have outletports 44 arranged at anangle .to the axes oi the tubes to direct theairat the proper angle on the lvanes I 8 on the rotor, the outer ends ofthe tubesbeing connected by pipes 46 to avsource of compressed air. v

From the above it will be seen that the inner gimbal is normally mountedonrthe small ball bearings 26 therebyV minimizing the frictiona] res'istance of'rotation, the supports for these small bearings beingprovided by the cantilevers 22 which .permit yielding movement of thebearings in response to a force acting on the gimbal normal to its axisof rotation. The clearance between the inner gimbal and the largebearings 32 is so small that upon a slight yielding movement of thecantilevers, the large bearings 32 become elective to appreciable forceacting normal to itsaxis of ro- Mounted onthe sleeves 20 between thesmall ball bearingsr26 and the adjacent portion of the outer gimbal I0are large ball bearings 32 provided with balls 34 which are relativelylarge as compared with the balls 30 ofthe bearings 26. Projectingoutwardly from opposite sides of the gimbal I4 are circular flanges 36which surround the large bearings 32 and are normally slightly spacedtherefrom, .'asillustrated in Fig. 2, so that these bearings arenormally ineffective to support the inner gimbal I 4.' In the event thatthe inner gimbalis subjected to an abnormal load normal to its axisofrotation the flexing of the cantilever suDpOIrtSfor the small ballbearings will cause the ange 36 to engage the large bearings 32 asindicated in Fig; 4, which thereby absorb the greater part of the' loadon'the gimbal and thus limit the load applied to the small bearings 26.Hence, it ispossible normally to support the inner gimbal on bearingswhich are of suflicient size to withstand normal loadingonjthegimbalbutfare not sufficiently large to'withstand any abnormal loadsupport thegimbal, thereby limiting'the load applied tothe small bearings. VWhenthe gyroscope is used in connection with the course control mechanism ofa torpedo this .abnormal force is of slight duration at the timeoflaunching the torpedo after which the cantilevers assume their normalpositions as shown in Fig. 2 and the gimbal is supported solely by thesmall bearings 26, the frictional resistance toA rotation of which is soslight that there'is no tendency of the inner gimbal to be moved out ofrits normal horizontal plane as the torpedo changes its depth in thewater.

While the bearing assemblyhas been described v particularly inconnection with a gyroscope, it will be obvious .that .it maybeusedingthe mounting of any rotatably mounted memberlvvhere it isVdesired normally to maintain the frictional drag on the member at anextremely lowjvalue, but providing supplemental support forjtheV memberto absorb abnormal forces acting thereon.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is;

1. In combination, a supporting member, an

element rotatably carried thereby, small ball bearings by which saidelement is carried by said supporting member, means mounting said ballbearings in said supporting member for yielding movement normal to theaxis of rotation of said element, large ball bearings carried by saidsupporting member adjacent to said small ball bearings, and meanscarried by said element normally concentric with and surrounding saidlarge ball bearings in spaced relation thereto but being arranged toreceive support from the large ball bearings upon movement of the smallball bearings in response to a force acting on said element transverselyof its axis of rotation.

2. In combination, a supporting member, an element rotatably carriedthereby, small ball bearings by which said element is carried by saidsupporting member, cantilevers carried by said supporting member andsupporting said ball bearings for yielding movement normal to the axisof rotation of said element, large ball bearings carried by saidsupporting member outwardly of said small ball bearings, and means rigidwith said element normally concentric with and surrounding said largeball bearings in spaced relation thereto, said means being arranged tobe supported by said large ball bearings upon yielding movement of saidsmall ball bearings.

3. In a gyroscope having an outer gimbal and an inner gimbal, meansrotatably supporting said inner gimbal from said outer gimbal comprisingsmall ball bearings carried by the outer gimbal for yielding movementrelatively to the axis of rotation of the inner gimbal, large ballbearings carried by the outer gimbal outwardly of said small ballbearings, said inner gimbal having portions surrounding said large ballbearings in spaced relation thereto but being arranged to be supportedby said large ball bearings upon yielding movement of said small ballbearings in response to a force acting on the inner gimbal transverselyof its axis of rotation.

4. In a gyroscope having an outer gimbal and an inner gimbal, meanssupporting said inner gimbal for rotation from said outer gimbalcomprising a pair of small ball bearings, inwardly extending cantileverscarried by said outer gimbalr and supporting said small ball bearingsfor yielding movement transversely of the axis of rotation of the innergimbal, large ball bearings carried by said outer gimbal outwardly ofsaid small ball bearings and fixed in positions concentric with thenormal positions of the small ball bearings, and flanges on said innergimbal surrounding said large ball bearings in spaced relation thereto,said flanges being arranged to be supported by said large bearings uponyielding movement of said small ball bearings in response to a yforceacting on said inner gambal normal to its axis of rotation. f"

5. In a gyroscope having an outer gimbal, an inner gimbal rotatableWithin the outer gimbal, and a rotor carried by the inner gimbal, smallball bearings acting normally to support the inner gimbal from the outergimbal, cantilevers carried by the outer gimbal and supporting saidsmall ball bearings for yielding movement normal to the axis of rotationof the inner gimbal, said cantilevers having passageways therethroughproviding for the admission of an impelling fluid to drive the rotor,large ball bearings carried by the outer gimbal between the smallbearings and the gimbal, outwardly extending circular flanges carried bythe inner gimbal and surrounding said large bearings in spaced relationthereto but being arranged to be supported thereon upon flexing of thecantilevers in response to a shock load on the gyroscope normal to theaxis of rotation of the inner gimbal.

6. In combination, a supporting member, an element rotatably carriedthereby, small ball bearings acting as combination journal and thrustbearings for said element, means mounting said ball bearings in thesupporting member for yielding movement normal to the axis of rotationof said element, large ball bearings carried by said supporting memberadjacent to said small ball bearings and normally out of contact withsaid element but arranged to act as journal bearings for said elementupon movement of said element in response to an abnormal radial loadthereon, and means mounting said element for axial movement relativelyto said small bearings in response to an excessive axial load thereon,whereby the large bearings act as thrust bearings for said element.

7. In combination, a supporting member, an element rotatably carriedthereby, small ball bearings by which said element is carried by saidsupporting member, cantilevers carried by said supporting member andsupporting said ball bearings for yielding movement normal to the axisof rotation of said element, said cantilevers being provided withshoulders arranged to engage the inner races of said ball bearings toprevent outward movement of the ball bearings relatively to saidelement, large ball bearing members carried by said supporting memberoutwardly of said small ball bearings, said element having a portionnormally concentric with and surrounding said large ball bearings-inspaced relation thereto and arranged to be supported by said large ballbearings upon yielding movement of said smallball bearings, and yieldingmeans carried by said element engageable with the outer races of saidsmall ball bearings, whereby the element is normally supported againstaxial movement, said yieldably means permitting axial movement of saidelement in response to an excessive axial load thereon whereupon theelement moves into engagement with one of the large ball bearings whichabsorbs the axial load on the element.

8. In a gyroscope having an outer gimbal and an inner gimbal, inwardlyextending yieldable cantilevers carried by said outer gimbal and havingreduced inner portions providing shoulders, small ball bearings carriedby the reduced portion of the cantilevers the inner races of saidbearings being engageable With the shoulders formed on the cantilevers,said inner gimbal being carried by the outer races of said small ballbearings for yielding movement transversely to the axis of rotation,large ball bearings carried by the outer gimbal outwardly of and inspaced relation to the small ball bearings and to the inner gimbal, saidinner gimbal having portions arranged to be supported by said large ballbearings upon Vmovement of the inner gimbal transversely of its axis ofrotation, spring members carried by the inner gimbal engageable wi-ththe other races of the small ball bearings whereby the small bearingsnormally act as thrust bearings for the inner gimbal, said springmembers permitting axial movement of the inner gimbal in response to anexcessive thrust load whereupon the inner gimbal moves into engagementwith one of the large bearings which absorbs the excessive Ithrust load.

CHARLES C. BELL.

